What is the resident tax return if there is additional income other than salary?…

Depending on the case, you may need to make a declaration.
In the case of income tax, manuscript fees and diplomacy fees are to be withheld at the time of payment, and the tax amount will be recalculated by adding it to employment income at the time of final tax return.
However, if the annual salary income is 20 million yen or less and the total annual income other than salary income (manuscript fee, diploma remuneration, etc.) is 200,000 yen or less, you do not need to file a final tax return. It is not supposed to be.
However, in the case of inhabitant tax, unlike the income tax, the tax amount is calculated by adding it to employment income regardless of the amount of income.
In your case, if you file a final income tax return for the manuscript fee, you will be considered to have filed a resident tax and you do not need to file a resident tax, but if you do not file a final tax return, you must file a resident tax return is needed.